Ireland as temporary relocation for work?

My husband works for a global company and may have the opportunity to go to Ireland to work on a project. Could be 2 weeks or 2 months. His job will take care of most of the details for him I'm sure however, I want to go too! ( Actually its a bucket list item for me) We will both of course have our passports and this will be my first trip abroad.

I have read many posts on this subject and seem to get mixed messages. The company will take care of the details housing, ect but my question is this, What other than my passport will I need to spend these 2 weeks -2 months with him?

While he works I plan on packing my Nikon and spending the majority of my time traveling Ireland and photographing my journey while learning the culture and meeting new friends. Yes I'm wearing my green tinted lenses:-)
Thank you in advance for any advice.

Added (1). I'm sorry I overlooked the important part, yes we're both born and raised in
the US. I will read the links you posted.

A good long question, but the main information is missing. What's your nationality? Your question was obviously asked from Y! A United States but not everybody living in the US Is a US Citizen who gets leave to enter Ireland for 90 days on arrival.
http://www.citizensinformation.ie/en/moving_country/moving_to_ireland/coming_to_live_in_ireland/visa_requirements_for_entering_ireland.html.
http://travel.state.gov/travel/cis_pa_tw/cis/cis_1145.html#entry_requirements.